A wide variety of cylinder locks of the pin tumbler type are known. In an effort to provide enhanced security, cylinder locks having a plurality of coaxial pins in each chamber have been developed. Locks of this description are disclosed in U.S. Pat. Nos. 593,436; 1,095,500; 3,818,732; and 4,142,389. Such locks, while providing a relatively high level of security, have a severe cost disadvantage in that they are extremely difficult and time consuming to assemble, master and service.